Controversy has continued for over a century over the structure of water, which is crucial to humankind. "Continuity model" that the origin of water anomaly, which is known to exhibit various peculiar properties not found in other liquids, such as maximum density at 1 ° C, is due to a structure with a wide continuous distribution. (Proposed by Popple et al.) And the "mixed model" (proposed by Roentgen, Pauling et al.), Which is based on a two-component structure, because there was no direct evidence.
But now, a group at the Institute of Industrial Science, University of Tokyo has found evidence to settle this long-standing unsolved problem.By simulating a general water model and detailed analysis of the latest X-ray scattering experiment data, two peaks are hidden in the apparent "first diffraction peak" in the structural factor of water. I discovered that.
One of the hidden peaks is caused by the density wave related to the regular tetrahedral structure formed in the water, and the other peak is caused by the density wave related to the more disordered structure. It is said that.This is a result of strong support for the existence of two types of structures in water: regular structures and messy structures.
This result is expected to show the validity of the phenomenological theory based on the two-state model that water is a coexistence state of two states, and to put an end to the long-standing debate over the structural origin of water peculiarity. By contributing to the understanding of the water structure of various systems such as not only pure water but also electrolyte solutions and water in the living body, it is considered that it will greatly spread to the fields related to water.
Paper information:[Journal of the American Chemical Society] Direct Evidence in the Scattering Function for the Coexistence of Two Types of Local Structures in Liquid Water
